Gravely L won't start hot

firhead

Member
My Gravely L starts good after sitting for a day or more, but won't re-start right after its been run. Any ideas?

Thanks
firhead
 
Not a lot of information to go on, but comes down to spark, fuel or compression...

Have you checked for spark when it fails to start?
No spark hot can be points (if so equipped) out of adjustment, burned, dirty, bad condensed, weak coil, bad spark plug.

Fuel: Dirty carb, poor fuel delivery, flooding, vapor lock or fuel boiling, caused by exhaust leaking toward carb, tank, or fuel line, water in fuel, non vented fuel cap, clogged air filter.

Compression: Tight valve clearance, sticking valve, broken valve spring.
 
All model "L" machines are magneto. If you have a Wico mag they are not the best. F&M are the hottest spark. You need to learn how to pull over a Gravely fast enough too. A guy showed me years ago and he was right. Hard to describe but you actually try to lift the machine off the ground! Pull with your knees and NOT your arms sort of like lifting a heavy load. They are very easy to flood and when hot they can vapor lock kinda sorta. Try going to Hi-Test gas. Just might cut down the vapors and let you restart. No choke when hot. Let us know.
 
Check the fire to the plug asap when the engine is hot. I would install a new condenser to see if that fixes the problem. The coil may be getting weak when the engine is hot. With weak magnets I don't think it would start hot or cold.
I have a mag off an old walk behind Standard Twin
that has weak magnets. When you touch them with a screwdriver they have no magnetism or very little. It's a Wico mag. Hal
 
Here's a picture of that Wico mag. Hal
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Do you have the air deflectors on it? The sheet metal pieces the curve around the sides of the jug and cover the top of the head? Without them the fan can't cool the engine right and the heat from the jug will get the carb very hot sometimes causing boiling gas and vapor lock. Is the fan belt tight enough to be running the fan at speed? Are the fins on the jug and head blocked with mud, dust, dirt and plant material? All these can lead to a very hot running Gravely that's hard to restart.

How is your fuel flow? Is there crap in the sediment bowl? Are any fuel lines kinked or crimped? Do you have a good flow out of the carb bowl? If not, fix that and see what happens.

A weak condensor might fail when hot. It's not bad to replace. Check the points for condition and gap. Check the plug wire too, they degrade and it needs to be solid core, not an automotive type wire. Check the condition of the mag cap too, cracks or even dirt and oil can cause weak spark.

A warm Gravely should start on the 1st pull every time.
 
OK - I've refined the situation somewhat. Now, it won't start at all. Have plenty of spark; if I remove plug, pour a bit of gas in cylinder and reinstall plug, I get about three seconds of run, then nothing. Gas pours out the bottom of carb when I open small needle drain at bottom, so I figure I've got fuel running THROUGH the carb - so what's happening?
Thanks for all the input.
 
Hold your hand over the throat of the carburetor while a helper cranks over the engine to see if you have good suction on your hand. Poor suction
is an indication of low intake manifold vacuum. You may have a worn cylinder, weak rings and valves may leaking during the compression stroke. Hal
 
Probably the jet is plugged with gunk and not letting fuel through. Could be a valve or ring issue, but I'd start with a a carb cleaning.
 
Appreciate the advice. I don't think its a ring/valve problem because it still seems to have OK power when it DOES run, and uses no oil. In that I have decent spark, I guess I have some kind of carb problem, as has been mentioned. Will pull it and clean it; any suggestions on setting main jet (one with the little T-handle?).

Thanks again
 
With the engine at wide open throttle open the main jet adjusting screw until it starts to smoke. Then close it until it quits smoking. If you're working the engine under load you may need to open it some more. Hal
 
I have a Toro mower and a Wards tractor both have that main jet adjusting screw. I haven't had to adjust them in about 40 years. Hal
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